So is it ash? mahogany? alder doesn't really have noticeable pores... If you live in an area that has potent strippers, that seems like the only way you can remove residual paint from pores. Strip most of the paint off first, and then use a stiff plastic bristle scrub brush soaked in water to scrub paint from the pores. (using a water rinse stripper) After the wood is clean and dry - sand using a your sandpaper over a wood block to keep it flat when sanding.
It's paulownia, so consider it like ash. What you describe is about what I was planning to do - sand off most of the finish and then use a stripper to get any residual finish off that's down in the pores.
Thanks mucho for the advice.

green